Decolgen FX Mechanism of Action

Pharmacology: DECOLGEN FX acts as an analgesic-antipyretic, antihistamine and nasal decongestant. Paracetamol produces analgesia by elevation of the pain threshold and antipyresis through action on the hypothalamic heat regulating center. Pseudoephedrine HCl is a sympathomimetic amine which provides relief of nasal and sinus congestion. Chlorpheniramine Maleate is an antihistamine which helps provide relief of runny nose, sneezing, watery and itchy eyes.
Pharmacokinetics: Paracetamol is readily absorbed from the gastro-intestinal tract with peak plasma concentration occurring about 10 to 60 minutes after oral administration. Paracetamol is distributed into most body tissues. It crosses the placenta and is present in breast milk. Plasma protein-binding is negligible at usual therapeutic concentrations but increases with increasing concentrations. The elimination half-life of Paracetamol varies from about 1 to 3 hours. Paracetamol is metabolized predominantly in the liver and excreted in the urine mainly as the glucuronic acid and sulphate conjugates. Less than 5% is excreted as unchanged Paracetamol.
Pseudoephedrine HCl is readily absorbed from the gastrointestinal tract. It is excreted largely unchanged in the urine with small amounts of its hepatic metabolite. It has a half-life of about 5 to 8 hours; elimination is enhanced and half-life accordingly shorter in acidic urine. Small amounts are distributed into breast milk. Concentration of pseudoephedrine in milk were consistently higher than in plasma; the half-life in both fluids was between 4.2 and 7 hours. Assuming a generous milk secretion of 500 mL over 12 hours, it was calculated that the excreted dose was the equivalent of 250 to 330 mcg of pseudoephedrine base, or 0.5 to 0.7% of the dose ingested by the mothers.
Chlorpheniramine Maleate is absorbed from the gastrointestinal tract, peak plasma concentrations occurring about 2.5 to 6 hours after administration by mouth. Bioavailability values of 25% to 50% have been reported. Chlorpheniramine appears to undergo considerable first-pass metabolism. About 70% of Chlorpheniramine in the circulation is bound to plasma proteins. There is wide interindividual variation in the pharmacokinetics of Chlorpheniramine; values ranging from 2 to 43 hours have been reported for the half-life. Chlorpheniramine is widely distributed in the body, including passage into the CNS. Chlorpheniramine Maleate is extensively metabolized. Metabolites include desmethyl and didesmethylchlorpheniramine. Unchanged drug and metabolites are excreted primarily in the urine; excretion is dependent on urinary pH and flow rate. Only trace amounts have been found in the faeces. More rapid and extensive absorption, faster clearance, and a shorter half-life have been reported in children.